Conversion of hydrocarbon oils



April 12, 1938; c. H. ANGELL CONVERSION OF HYDROCARBON OILS Filed May 16, 1935 FRACTIONATOR FURNACE 2 RECEIVER FURNACE FURNACE m w R m w N ES u ML from its Patented Apr. 12, 1938 UNITED! STATES PATENT --oFF c-s 2,113,689 CONYEBSION F HYDBOQARBON OILS Charles 11. Angeli, outage, 111., assignor to ma versal Oil Products Company, Chicago, IlL, a corporation of Delaware Application May 16, 1935, Serial N0. 21,745

3 Claims. (Cl. 196-49) This inventionrefers to improved process for the fractional distillation of hydrocarbon oils of relatively wide boiling range accompanied by conversion of their low-boiling fractions, together with the intermediate conversion products oi the process, and reduction of their high-boiling fractions to coke, together with residual liquids re,-

sulting from said conversion. a

The present invention is particularly directed 16 to the. treatment of hydrocarbon oils of relatively @vide boiling range such as crude petroleum, topped crude and the like which contain an appreciable quantity f high-boiling materials of a relatively -high'cok -,forming nature unsuitable for conversion under'the relatively severe ccnver-' .sion conditions best suited to the treatment of their lower boiling components.

In accordance with the invention the highboiling fractions of-th'e charging stock of a rela- 'tively high coke-forming nature are separated mingling the charging stock with hot'conversion products of the process in the stage of the system wherein separation of vaporous and residual liq- 5 uid conversion-products is accomplishedits lowboiling components being thereby vaporized and subjected to .fracti'onation' together with the vaporous conversion products of the process and to the further treatment afforded the inter- I 0 mediate conversion products (reflux condensate) resulting from said fractionation while said high-- boiling components of the charging'stock com-. mingle with the residual liquid conversion products and are subjected therewith to coking.

5 Coking ofthe high-boiling fractionsoi thecharg ing stock and the residual liquid conversion products may be accomplished, in accordancewith the invention, by passing the commingled oils through a heating coil into one or a plurality of enlarged E40 coking chambers; the qils being subjected in the heating coil to a temperature sufiicient to effect reduction of the oil to substantiallydry coke in the succeeding coking zone-without allowing it to remain in the heating coil for a sufficient length of time to permit any substantial formation and may be employed in conjunction with the use of lower boiling components by com a heat carrying-medium. supplied to "the coking zone. I

In accordancewithcne method of operation, the intermediate conversion products of the process and the low-boiling fractions of the char ng stock may be separated, by fractional condensation in the fractionator of the system to which they are supplied in vaporous-state, into selected relatively low-boiling and high-boiling fractions, said low-boiling and high-boiling frac- 1g tions being subjected to independently controlled conversion conditions in separate heating coils of the system: When this inethod of operation is employed a regulated portion or all of the highly heated relatively low-boiling products from the 15 heating coil to which said low-boiling fractions are supplied may; when desired, be introduced into. the coking zone as a heat carrying medium for assisting the coking operation.

Another feature of the invention comprises rea turning the vaporous products from thecoking zone to the vaporizing chamber of the cracking system wherein said separation of vaporous and liqu d conversion products and substantial vaporization of the charging stock is accomplished. BM

this method of operation the heat contained in the relativelyhot vaporous products from the coking zone isutilized to assist vaporization of the lowboiling fractions of the charging stock and this heat exchange serves, on the other hand, to cool 30 the vaporous products from the coking zone sufficiently ,to effect the removaltherefrom of entrained heavy liquids and similar high-boiling materials of a high coke-forming nature and saidhigh-boiling materials commingled in the va- 5 porizing chamber with the residual liquid conversion products and the non-vaporous hi'ghboiling fractions of the charging stock and are returned therewith to the coking zone.-

In one embodiment, the invention comprises 4o subjecting an oilrecover'ed from within the systern to conversion'conditions of cracking temperature and superatmospheric pressure in'a heating coil and communicating reaction. chamber, with drawing vaporous and liquid conversion products 45 from the reaction chamber and introducing the same into a reduced pressure vaporizing chamber wherein separation of vaporous and residual liquid conversion'products is accomplished, supplying hydrocarbon oil charging stock, for the 5 process to said vaporizing chamber whereby its low-boiling components are vaporized and separated from its non-vaporous high-boiling components, withdrawing residual liquid conversion products and said high-boiling fractions for the charging stock from the vaporizing chamber and subjecting the same to coking in a coking chamber, returning vaporousproduc'ts from the coking chamber to said vaporizing chamber, subjecting vaporous products'from the vaporizing chamber,

comprising said low-boiling fractions of the charging stock and the vaporous products from thecracklng and coking operation, to fractionation whereby their insufliciently converted components are condensed as reflux condensate and separated into selected relatively low-boiling and high-boiling fractions, subjecting fractionated vapors of the desired end-boiling point to condensation, collecting andseparating the resulting distillate and gas,- supplying the high-boiling fractions of said reflux condensate to the first mentioned heating coil for said conversion, subjecting the selected low-boiling fractions oi. said reflux condensate to independently controlled conversion conditions of cracking temperature and superatmospheric pressure in a separate heating coil, introducing a regulated portion of the resulting highly' heated products into the coking chamber and supplying the remainder to said vaporizing chamber.

The accompanying diagrammatic drawing illustrates one specific form of apparatus in which the process of the present invention as outlined in the'foregoing specific embodiment may be accomplished. The apparatus illustrated also provides for various alternative methods of operation, some of which have been previously mentioned and all of which are entirely within the scope of the present invention. -It will be understood, of course, that the various alternative y-inethods of operation illustrated and described I are not equivalent but may be selected to suit requirements and serve to give the process greater flexibility. V

Referring to the drawing, heating coil 1 is located within a furnace 2 of any suitable form and the oil-supplied thereto, as will be later more fully described, is heated to the desired conversion temperature, preferably at a substantial superatmospheric pressure, and the heated products are discharged through line 3 and valve 4 into reaction chamber 5. Chamber -5 is also preferablymaintained at a substantial superatmospheric pressure and, although not illustrated in the drawing,-this zone is preferably insulated in order to prevent'the excessive loss of heat therefrom by radiation so that conversion of the heated oil supplied thereto, and particularly its vaporous components,

55 may continue in the reaction chamber. In the ;'case here illustrated, both vaporous and liquid conversion products are 'withdrawn in com-' mingled state from the'lower portion of cham- 70 chamber 9 by means ofheat recovered i'romthe her 5 through line 6 and valve I and are introducedthrough line 8 into vaporizing chamber 9.

Simultaneous with the operation above described, hydrocarbon oil charging stock for the process issupplied through line lland valve H to pump l2 by means of which it is fedthrough line l3 and may be introduced through line ll, valve l5 ,and line .39 into vaporizing-chamber 9 to cbmmingle therein with the hot conversion products of the process supplied to this zone. The charging stock is subjected to vaporization in 75 separated from itslower boiling vaporous com ponents. In order to assist vaporization of the charging stock and further vaporization of the liquid conversion products supplied to chamber 9 from the reaction chamber the vaporizing chamber is preferably operated at a substantially reduced pressure relative to that employed in the reaction chamber.

It is also within .the scopeof the invention, instead of supplying all of the charging stock direct to vaporizing chamber 9, to introduce a regulated portion or all of the charging stock through valve I6 in line l9 into thelowe'r portion of reaction chamber 5 to commingle with and cool the conversion products withdrawn from this zone to chamber 9 in the manner previously described, or when desired, a portion or all of the charging stock may be commingled in line 6 or in line 8 with the stream of conversion products passing from chamber 5 to chamber 9, although means for accomplishing this are not illustrated in the drawing. The present invention also contemplates the introduction of a regulated portion or all of the charging stock, when desired, through-line I1 and valve it into the upper portion of vaporizing chamber 9, wherein suitable baiiies or other fractionating means, not illustrated, may be employed, the charging stock are fed through line 22 and may be directed through line 23, valve 9| and line 29 into coking chambers 39 and 39, being supplied thereto at any desired point or plurality of "points by means of a plurality of lines 32 and 32' controlled by the respective valves 33 .and 33', or the high-boiling oils-from chamber 9 may be directed from line 22 through line 24, valve 25, heating coil 26, line 28 and valve 29 into coking chambers 39 and 39' through one or a plurality of the respective lines 32' and 32' controlled by the respective valves 33 and 33'. Y I

Heating coil 26 is located within a suitable furnace 21 and, although indicated in a conventional manner in the drawing, the form of furnace 21 and heating coil 26 is preferably such that relatively high rates of heating aPe obtained in this zone so that the heavy oils supplied thereto are quickly heated to a temperature sum'cient to eflect their subsequent reduction to coke in coking chambers 30 and 39' without allowing them to remain in the heating coil for a sumcient length of time to permit any substantial formation and depositionof coke in the heating coil and the lines communicating with the coking chambers.

Coking chambers 39 and 39' are similar zones wherein reduction of the relatively heavy oils from chamber 9 to substantially .dry coke is accomplished. It will be understood that although two cokingchambers are shown in the drawingone or any desired number of a plurality of such zones may be employed when desired and, when a plurality is employed, the chambers may be simultaneously operated or, preferably, are alternately operated, cleaned and prepared .for

further operation in order that the coking stage of the process, in common with the rest'ofthe system, may be operatedcontinuously. The coke produced may be allowed to accumulate within' the coking chamber to be removed therefrom in any.suitable well known manner, not illustrated, after the operation of the chamber is completed.

, Chambers 30 and 30' are provided with suitable ing medium into the chambers,'after' theirxoper- --'ation has been completed and after they have been isolated from the rest of the system, in order to hasten cooling and facilitate the removal of coke. Vaporous products are withdrawn from chambers 30 and 30' through the respective lines 36 and 36' controlled by the respective valves 31 and 31' andare directed through line 38 into vaporizing chamber 9, entering this zone at any desired point. In .the case here illustrated the vaporous products from the coking zone commingle in line 38 with hydrocarbon, oil charging stock for the process which is supplied to the vaporizing chamber, although they may, of course, be otherwise supplied to the vaporizing chamber in any desired manner.

The vaporous products from chamber 9,'includ'- ing thegomponents of the charging stock vaporiz'ed in this zone as well as the vaporous conversionproducts from the reaction chamber and from the coking chambers which remain uncondensed in this zone, are directed through line 39 and valve 40 to fractionation in fractionator M, wherein their components boiling above the range of the desired ilnal light distillate product of the process.

are condensed as reflux condensate. Fractionated vapors of the desired end-boiling point are withdrawn, together with uncondensable gas produced by the process, from the upper portion of fractionator ll through line 42 and valve 43 and aresubjected to condensation in condenser 44. The resulting distillate and "gas passes through line 45 and valve 46' to collection and' separation in receiver 41. Uncondensabie gas may be released from the receiver through line 48 and valve 49. Distillate is withdrawn from receiver 41 through line 50 and valve ii to storage or to any desired treatment. When desired, a

regulated portion 61 the distillate collected in re-.

' ceiver 4] may be recirculated by well known means, notshown in the drawing, to the upper 4| may collec zoneto be withdrawn therefrom through line 52 60" portion of fractionator 41 to serve as a cooling and refluxing medium for assisting fractionation of the vapors and to maintain the desired vapor outlet temperatures from the irictionator. The reflux tondensate-formed in, fractionator within the lower portion of this and valve 53 topump 54 b means of which it is v supplied through line 55 and valve ii to conversion, as heretofore described, in heating coil I.

It is,fhow ever, also within the scope of the invention to separate the reflux condensate formed in fractionator-l i into selected relatively low-boiling and high-boiling fractions in which case only the high-boiling fractions are supplied.-.;as described,

. to heating coil l v; 'the'low-boilingfractions beingzone and,

removed fr'om'the fractionator at-any-suitable I intermediate point or plurality. ofpoints' in this in'the case here illustrated, the low-- boiling reflux condensate is directed throughline "and valve 58 to pump 5 9v by means of which it is supplied through line. 80 and valve ii to separate .7

conversion in heating coil i l.

, products from heatingcoil 62,- instead of commingling in line 8 with the conversion products from chamber Ii, may be separately supplied tothe vaporizing chamber at any desired point or plurality oj points in this zone, by wellknown means notshown in the drawing. Provision is also made for supplying a regulated portion or all of the hot conversion products from heating coil 62 into coking chambers 30 and 30' to serve as a heat-carryingmedium for assisting reduction of the residual materialsin the coking chambers to substantially dry coke. This may be accomplished by means of line 61, valve 68 and one or more the various branch lines 32 and 32' controlled by the respective valves 33 and 33'; It is particularly desirable, in case heating coil 26 is not employed, to employ heating coil 62 for separate conversion of the relativelyulow-boiling oils from fractionator 4i, and to supply regulated quantities of the highly heated products from heating coil 62 to the toking zone to furnish additional heat thereto fo assisting the coking opera- .tion. It is also entirely within the scope of the present invention to accomplish reduction of the high-boiling oils from chamber 9 to coke by further heating of the same in heating coil 26 in conjunction with the use of a heat-carrying medium in the coking chambers. The invention is,

. however, not limited to either of the methods of coking illustrated and described butmay employ any suitable well known method and means such as externally heated coking ehambersior suitablecoking ovens or retorts, either alone or in. conjunction with either or both of the specific-methods illustrated. I V

In an apparatus such ,as illustrated and above described, the preferred range of operating'conditions foraccomplishing the objects of the invention may be approximately as follows: The heating coil to which the total reflux condensate, or

only high-boiling fractions of the reflux condensate, are supplied may utilize a conversion temperature, measured at the outlet therefrom, ranging, for example, from 850 to 950 F'., preferably with a superatmospheric pressure at this point in the system of from, 100 to 500 pounds, or thereabouts'per square inch. The pressureemployed in the reaction chamber may be substantially equalized or somewhat reduced relative to the pressure employed in the preceding heating coil. The vaporizing chamber is preferablyoperated at a substantially reduced pressure relative to that employed in the reaction chamber which may range, for'example, from 100 pounds, or thereabouts, per square inch, down to substantially atmospheric pressure. The fractionating, condensing and collecting portionsvof the system'may employ pressures substantially the same or-somewhat lower than that employed in the vaporizing chamber. When a heating coil is employed tor heating of the high-boiling oils from the vaporizing chamber, prior tothe ir introduction into the "coking chamber, the temperature employed at the outlet, from this zone is preferably of the order of 900.110 1000' m, orthereabouts, with a pressure at v this point in the system which may range, for example, from a slight super-atmospheric pressure of 30 pounds or less per square inch up to asuperatmospheric pressure of pounds, or more, per

. square inch. The pressure employed in the coking chambers is preferably somewhat higher than that employed in the vaporizing chamber in order to permit the return of vapors from the coking chamber to the vaporizing chamber without the use of a pump or compressor and may range upward from 30 pounds, or less, per square inch to 200 pounds, or more, per square inch superatmospheric pressure. When'aseparate heating coil is employed for conversion of the lowboiling fractions of the reflux condensate the conversion temperature employed at the outlet from this zone may range, for example, from 900 to 1050 F., .or thereabouts, and preferably a superatmospheric pressure of the order o1 200 to 800 pounds, or more, per square inch, is employed at this point in the system, although lower pressures down to substantially the same as that employedin the coking chamber may be utilized, when desired.

As a specific example of one of the many possible operations of the process of the present invention as it may be accomplished in an apparatus such as illustrated and abovedescribed,

the charging stock comprises a California crude of about 205 A. I. gravity containing approximately 12 percent of material boiling up to 400 action chamber operated-at substantially the same pressure. Both vaporous and liquid products from the reaction chamber are introduced into the vaporizing chamber which is maintained at a superatmospheric pressure of approximately pounds per square inch and from which residual. liquid is withdrawn and subjected in a separate heating coil to a temperature of approximately 985 F. at a superatmospheri'c pressure of about 60 pounds per square inch and then introduced into alternately operated coking chambers maintained at substantially the same pressure.

Vaporous products from the coking'chambers are returned to the vaporizing chamber and the vaporous products from this zone are subjected to fractionation for the formation of said reflux condensate. The low-boiling fraction of the reflux condensate, which boil within the range-of substantially 350 to 500 F., are subjected in another separate heating coil to anoutlet conversion temperature of approximately 975 F. at a superatmospheric pressure of about 600 pounds per squareinch. A portion of the highly heated products from the last mentioned heating coil is introduced into the body of residual materials undergoing coking in the coking chambers and the remainder supplied-to the vaporizing chamber. This operation will produce, perbarrelof charging stock, approximately 55 percentot motor fuel having an octane number ofiapproximately 70 by the reaction chamber and introduced into a reduced pressure vaporizing chamber wherein separation of vaporous and liquid conversion products is accomplished, the improvement which comprises introducing hydrocarbon oil charging stock 'for the process, comprising an oil of relatively wide boiling range, into said vaporizing chamber whereby it is subjected to vaporization and thereby separated into selected relatively low-boiling and high-boiling fractions, withdrawing non-vaporous residual'liquid conversion products and non-vaporous high boiling fractions of the charging stock from the vaporizing chamber, introducing the same into a coking zone and reducing the same therein to substantially dry coke, introducing vaporous products from the coking zone into the vaporizing chamber, fractionating the vaporous products from the vaporizing chamber and separating selected relatively low-boiling and high-boiling'fractions therefrom, returning the last-named high-boiling fractions to said heating coil for further conversion, subjecting the last-named low-boiling fractions to independently controlled conversion conditions of higher cracking temperatures and superatmospheric pressure in a separate heating coil, introducing a regulated portion of the heated products from said separate heating coil into the coking zone for the purpose of assisting the coking operations and supplying the remaining portion thereof-to the vaporizing chamber, and finally condensing the fractionated vapors.

2. In a process for the conversion of hydrocarbon oils wherein intermediate conversion products of'the process are subjected to conversion conditions of cracking temperature and superatmospheric pressure in a heating coil and communicating reaction chamber, both vaporous and liquid conversion products withdrawn from the reaction chamber and introduced into a reduced ing stock from the vaporizing chamber, heatingv the same to a cracking temperature under non coking conditions in a separate heating coil, in troducing the heated oil, into a coking zone and reducing the same therein to. substantially dry ,coke, supplying vaporous products from the coking zone to the vaporizing chamber, fractionating the vaporous products from the vapbrizing chamber and separating selected relatively low-boiling and high-boiling fractions therefrom, return-'- ing the last-named'high-boiling fractions to said heating coil for further conversion, subjecting the last-named low-boiling fractions to independently controlled conversion conditions .of higher cracking temperatures and superatmosphe'ric pressure in a'separate heating coil, introducing a regulated portion of the 'heated products from said separate heating coil into the coking zone.

products of the process are subjected to conver-- for the 9 F9 assisting the 605118 Operation 75 and supplying the remaining portion thereof to the vaporizing chamber, and finally condensing the fractionated vapors.

3. A conversion process which comprises heating hydrocarbon oil to cracking temperature under pressure in a heating coil and subsequently introducing the same to a separating chamber,

introducing charging oil for the process to said chamber and partially distilling the same there in, removing unvaporized oil from the separating chamber and distilling the same to coke in a coking chamber, introducing vapors from the coking chamber into the separating chamber, re-.

moving vapors from the separating chamber and fractionating the same to form a relatively heavy v chamber and into the coking chamber, and fin- 10 ally condensing the fractionated vapors.

CHARLES ANGELLQ 

